 So once a plant has been designed, built, and carefully tested, it begins to operate. But in operation it's necessary to ensure safety. And so there are a lot of arrangements taken to ensure the safety of an operating plant that we will see in the next subparts. The first one being the operating rules. Though the operating rules assemble the assumption and requirements coming from the design and that they should be complied with during a normal operation. The operating rules cover and we will see again here the defense in-depth principle. Prevention. This document is called the operating technical specification. For monitoring there are some periodic inspection and testing. And in mitigation there are the emergency operating procedures. Operating rules also include some rules about normal operation, radiation protection, environment surveillance, the organization of the operator and on-site and off-site emergency plans. So let's begin with the operating technical specification. There are sort of the highway codes for the operator with three main objectives. The first is to ensure that the plant operates inside the design basis and that the importance parameter are kept under control. And just to give an example, when we make the calculation of loss of current accident and the increase in pressure and temperature of the containment, there is an initial temperature considered in the calculation for the containment, which in that case is 50 degrees. So it's important that the normal operation to ensure that the temperature inside the containment remains under 50 degrees and this is including the operating specification. Another important aspect is to ensure the operability and availability of safety functions. Some of them are running permanently, they operate normally, but some of the others are on standby and it's important to check the condition for operability of all the safety functions. The third objective is to define the action to take in the event of exiting a safety limit, a safety parameter, or if there is some unavailability of safety system. And in that particular case, if one system is discovered to become unavailable, usually there is a sort of grace time which is in the order of depending on the type between one error or several hours or sometimes in days. And if the safety system is not put back in normal operation and not become again available, the reactor should be shut down at the end of this grace period. The second element of the operating rules are the periodic inspection and test. They are used to test the operability and design performance parameters of safety system and components which are in standby mode during normal operation. These tests are done depending on the system every two weeks or every months or at every outage each year. These periodic inspection tests also serve to detect any drift in the performance parameters from the authorized range even if the set points are complied with. If there is an evolution of the parameters, this should be taken into account and correction should remain. For passive system and passive components, these periodic inspections serve also to detect any potential degradation of the component by such phenomena as corrosion cracks and this is what we call that in-service inspection. So the third important elements of the operating rules are the emergency operating procedures, EOPs as we call them. The first instance of a transient of an accident sequence are covered by automatic action. So the wrecked scram or wrecked trip and the safety system actuation. And so the first role of the operator is to check the correct operation of this automatism and to maintain control of the installation. And the emergency operating procedures allow the operator to diagnose the event and to take pre-established action to take the reactor in a safe shutdown condition. Initial EOPs were event oriented. That is set for each design transient or design basis accident that were analyzed in the safety analysis report. Some predetermined actions were included in these EOPs. But the experience shows that reality might be somewhat different and the course of the transient of the accident might be the difference of what has been assumed as a design stage and they also could be a combination of events or failures that complicate the management of the plant. But a few finite numbers of physical parameters enable a physical characterization of the plant that correspond to a finite number of corrective actions. And so from these elements a very important new emergency operating procedures were developed which are called state oriented. So with state oriented procedures a priority is no longer to diagnose the event that had happened but to diagnose the actual plant condition of the state through the following parameters. The reactivity, the content of water in the vessel, whether the residual power is extract whether the colon system is broken the availability of steam generator and the containment integrity. The diagnosis of these parameters is repeated periodically and allows the operator to adjust the type of action to be undertaken.